Rename our allwpilib (which is now 2020) to not have 2019 in the name

Change-Id: I3c07f85ed32ab8b97db765a9b43f2a6ce7da964a
diff --git a/cmake/toolchains/gnu.toolchain.cmake b/cmake/toolchains/gnu.toolchain.cmake
new file mode 100644
index 0000000..cba08e7
--- /dev/null
+++ b/cmake/toolchains/gnu.toolchain.cmake
@@ -0,0 +1,134 @@
+cmake_minimum_required(VERSION 2.8)
+
+# load settings in case of "try compile"
+set(TOOLCHAIN_CONFIG_FILE "${CMAKE_BINARY_DIR}${CMAKE_FILES_DIRECTORY}/toolchain.config.cmake")
+get_property(__IN_TRY_COMPILE GLOBAL PROPERTY IN_TRY_COMPILE)
+if(__IN_TRY_COMPILE)
+  include("${CMAKE_CURRENT_SOURCE_DIR}/../toolchain.config.cmake" OPTIONAL) # CMAKE_BINARY_DIR is different
+  macro(toolchain_save_config)
+    # nothing
+  endmacro()
+else()
+  macro(toolchain_save_config)
+    set(__config "#message(\"Load TOOLCHAIN config...\")\n")
+    get_cmake_property(__variableNames VARIABLES)
+    set(__vars_list ${ARGN})
+    list(APPEND __vars_list
+        ${TOOLCHAIN_CONFIG_VARS}
+        CMAKE_SYSTEM_NAME
+        CMAKE_SYSTEM_VERSION
+        CMAKE_SYSTEM_PROCESSOR
+        CMAKE_C_COMPILER
+        CMAKE_CXX_COMPILER
+        CMAKE_C_FLAGS
+        CMAKE_CXX_FLAGS
+        CMAKE_SHARED_LINKER_FLAGS
+        CMAKE_MODULE_LINKER_FLAGS
+        CMAKE_EXE_LINKER_FLAGS
+        CMAKE_SKIP_RPATH
+        CMAKE_FIND_ROOT_PATH
+        GCC_COMPILER_VERSION
+    )
+    foreach(__var ${__variableNames})
+      foreach(_v ${__vars_list})
+        if("x${__var}" STREQUAL "x${_v}")
+          if(${__var} MATCHES " ")
+            set(__config "${__config}set(${__var} \"${${__var}}\")\n")
+          else()
+            set(__config "${__config}set(${__var} ${${__var}})\n")
+          endif()
+        endif()
+      endforeach()
+    endforeach()
+    if(EXISTS "${TOOLCHAIN_CONFIG_FILE}")
+      file(READ "${TOOLCHAIN_CONFIG_FILE}" __config_old)
+    endif()
+    if("${__config_old}" STREQUAL "${__config}")
+      # nothing
+    else()
+      #message("Update TOOLCHAIN config: ${__config}")
+      file(WRITE "${TOOLCHAIN_CONFIG_FILE}" "${__config}")
+    endif()
+    unset(__config)
+    unset(__config_old)
+    unset(__vars_list)
+    unset(__variableNames)
+  endmacro()
+endif() # IN_TRY_COMPILE
+
+if(NOT CMAKE_FIND_ROOT_PATH_MODE_LIBRARY)
+  set(CMAKE_FIND_ROOT_PATH_MODE_LIBRARY ONLY)
+endif()
+
+if(NOT CMAKE_FIND_ROOT_PATH_MODE_INCLUDE)
+  set(CMAKE_FIND_ROOT_PATH_MODE_INCLUDE ONLY)
+endif()
+
+if(NOT CMAKE_FIND_ROOT_PATH_MODE_PACKAGE)
+  set(CMAKE_FIND_ROOT_PATH_MODE_PACKAGE ONLY)
+endif()
+
+if(NOT CMAKE_FIND_ROOT_PATH_MODE_PROGRAM)
+  set(CMAKE_FIND_ROOT_PATH_MODE_PROGRAM NEVER)
+endif()
+
+macro(__cmake_find_root_save_and_reset)
+  foreach(v
+      CMAKE_FIND_ROOT_PATH_MODE_LIBRARY
+      CMAKE_FIND_ROOT_PATH_MODE_INCLUDE
+      CMAKE_FIND_ROOT_PATH_MODE_PACKAGE
+      CMAKE_FIND_ROOT_PATH_MODE_PROGRAM
+  )
+    set(__save_${v} ${${v}})
+    set(${v} NEVER)
+  endforeach()
+endmacro()
+
+macro(__cmake_find_root_restore)
+  foreach(v
+      CMAKE_FIND_ROOT_PATH_MODE_LIBRARY
+      CMAKE_FIND_ROOT_PATH_MODE_INCLUDE
+      CMAKE_FIND_ROOT_PATH_MODE_PACKAGE
+      CMAKE_FIND_ROOT_PATH_MODE_PROGRAM
+  )
+    set(${v} ${__save_${v}})
+    unset(__save_${v})
+  endforeach()
+endmacro()
+
+
+# macro to find programs on the host OS
+macro(find_host_program)
+ __cmake_find_root_save_and_reset()
+ if(CMAKE_HOST_WIN32)
+  SET(WIN32 1)
+  SET(UNIX)
+ elseif(CMAKE_HOST_APPLE)
+  SET(APPLE 1)
+  SET(UNIX)
+ endif()
+ find_program(${ARGN})
+ SET(WIN32)
+ SET(APPLE)
+ SET(UNIX 1)
+ __cmake_find_root_restore()
+endmacro()
+
+# macro to find packages on the host OS
+macro(find_host_package)
+ __cmake_find_root_save_and_reset()
+ if(CMAKE_HOST_WIN32)
+  SET(WIN32 1)
+  SET(UNIX)
+ elseif(CMAKE_HOST_APPLE)
+  SET(APPLE 1)
+  SET(UNIX)
+ endif()
+ find_package(${ARGN})
+ SET(WIN32)
+ SET(APPLE)
+ SET(UNIX 1)
+ __cmake_find_root_restore()
+endmacro()
+
+set(CMAKE_SKIP_RPATH TRUE CACHE BOOL "If set, runtime paths are not added when using shared libraries.")